Areas of endemism as a conservation criterion for Iberian gypsophilous flora: a multi-scale test using the NDM/VNDM program

The identification of areas of endemism is a crucial tool for both the interpretation of the spatial component of biological evolution and the plotting of priority areas as far as biodiversity conservation is concerned. Geographical isolation, aridity and special substrates are among the factors which can help to explain the restricted areas of the taxa. All these factors concur in the origin of the Iberian gypsophilous flora, rich in endemic and threatened species. Gypsum is a particularly demanding rock for plants, and gypsum outcrops are usually fragmented in space, in territories with arid conditions. Information on the presence of 71 gypsophytes was collected in 10x10km Universal Transverse Mercator (UTM). The distribution of these plants was used to plot the main areas of endemism for the vascular flora on Iberian gypsum outcrops. This was carried out using the eNDeMism/Visor of eNDeMism (NDM/VNDM) program and several grid cell sizes. A total of 51 areas of endemicity were identified and represented on a map according to their program selection frequency. The South East (SE) of the Iberian Peninsula was the only area selected in all the tests. The results were also compared with other factors of interest for the conservation of gypsophilous flora like genetic diversity of four gypsophytes.